Abstract Physical Layer Security (PLS) in Cognitive Radio Networks (CRN) improves the confidentiality. availability. and integrity of the external communication between the devices/ users. The security models for sensing and beamforming reduce the impact of adversaries such as eavesdroppers in the signal processing layer. https://www.roneverhart.com/Apple-11-inch-iPad-Pro-Wi-Fi-64GB-Space-Gray-2018-release/